The Protein Expression, Purification and Interaction Core (Core C) will provide instrumentation, expertise and service related to the cloning, over expression and purification of viral proteins and virus-like-particles (VLPs) as needed by each of the three project components. In addition, the Core will utilize the purified proteins and VLPs to measure interactions with other relevant ligands using surface plasmon resonance. This core will provide the following specific functions: (1) cloning and sequencing of wild-type and mutant genes encoding viral proteins into bacterial and insect cell protein expression vectors; (2) optimization of protein expression levels in the bacterial and insect systems; (3) purification of viral proteins; (4) expression, characterization and purification of VLPs; (5) quantitation of protein interactions with antibodies, RNA and proteins, polysaccharides and other viral proteins; and (6) synthesis of peptide arrays for fine mapping of monoclonal antibody epitopes.